1. Field of the Invention
The present invention relates to rigid telescopically arranged multi-cavity dispensing containers for flowable material, such as toothpaste, from which it is desired to dispense simultaneously two or more reactive substances which require separate storage until time of use. More particularly the invention relates to a disposable refill cartridge and reusable base combination. Most especially the invention provides a reusable base of improved separability from the disposable refill cartridge that can also be more rapidly manufactured.
1. The Related Art
Multi-cavity dispensing containers are useful in a variety of consumer products. These uses include the delivery of epoxy adhesives, skin treatment products, hair colorants and toothpastes. For several years in the U.S. Mentadent.RTM. toothpaste has employed a multi-cavity dispensing pump. Baking soda and hydrogen peroxide in respective flowable carriers are stored separately in different cavities of the pump. Absent separation, these ingredients would react and decompose in storage. Only upon dispensing do the ingredients mix together for use in a consumer's mouth.
The basic concept for a Mentadente product type packaging is disclosed in U.S. Pat. No. 4,687,663 (Schaeffer). Therein is described a rigid pump-type dual-cavity dispenser having two closely positioned but separate outlets. A respective dual material stream of peroxide and baking soda is extruded from these outlets. Among shortcomings of this disclosure is failure to consider the possibility that the two component streams might have different rheologies. These differences lead to improperly proportioned quantities of the two materials when being dispensed from the container.
U.S. Pat. No. 5,038,963 (Peffengill et al.) and U.S. Pat. No. 5,020,694 (Pettengill) resolve the problem of delivering two or more materials of different rheologies. A rigid piston type multi-cavity pump is reported having lower and upper body members. The lower body member has a base and two or more pistons attached. The upper body member has parallel cylinders for containing the flowable materials and an outlet mechanism for dispensing these materials. The lower end of the cylinders receive the pistons whereby the relative compression of upper and lower body members forces the flowable materials out through the outlet mechanism. This produces a single, banded unmixed stream of material that can be neatly and easily applied onto the narrow width of a toothbrush. Upper and lower members cannot be sold as separate independent units because pistons of the lower member are needed to seal the flowable material within the upper member. In addition, ridges formed on both the upper and lower body members prevent them from being pulled apart. After the contents of the pump are exhausted, both upper and lower body members must by necessity be discarded. Recyclability would be highly desirable for economic and environmental reasons.
U.S. Pat. No. 5,289,949 and U.S. Pat. No. 5,335,827, both to Gentile, report engineering improvements on the basic Mentadent.RTM.) pump which at least partially address the recyclability issue. A refill cartridge separately housing baking soda and peroxide is utilized in conjunction with a reusable base. Upon exhaustion of the toothpaste, the empty cartridge can be separated from the base and a refill inserted. The refill cartridge includes two hollow and separate parallel cylinders each having an upper end telescopically and slidingly accommodating a piston head. Unlike the non-refill version, the piston heads are tightly engaged with the upper body (refill cartridge) and are merely contactable with the upper end of hollow pistons formed in the lower body (reusable base). When refill and base are combined, a central portion on the underside of each piston head fits within a respective opening at the upper end of each piston. Contact between piston and cylinder is thereby maintained. Upon downward hand pressure on the refill, the piston presses against the underside of its respective head forcing same upward and causing the toothpaste stream to exit a dispensing mechanism at the top of the refill cartridge.
Beyond environmental and economic advantages, the refill concept has proved commercially quite successful in the Mentadente product. Yet further improvements would be desirable. It would be particularly useful to improve upon the ease of refill cartridge removability, especially to assist consumers afflicted with arthritic and other physical limitations. Another aspect requiring improvement is that of manufacturability. The hollow pistons of the base and piston heads with their central portions can only be molded at a relatively slow rate of production. Manufacturing speeds are inhibited by the relatively long cooling cycles necessary between each extrusion.
Another longstanding problem has been the difficulty of miniaturizing dual cavity pumps intended for sampling and travel.
Accordingly, it is an object of the present invention to provide a multi-cavity dispensing refill cartridge and reusable base system whose parts are easier for consumers to separate, especially inexperienced and physically challenged persons.
Another object of the present invention is to provide a multi-cavity dispensing refill cartridge and reusable base system whose piston and cylinder components can be more rapidly manufactured than those hitherto known.
Still another object of the present invention is to provide a multi-cavity dispensing refill cartridge and reusable base system in miniature sample size form (to deliver 0.5 ounces or less product).
These and other objects of the present invention will more readily be understood from the following summary and detailed description.